The MBL Physiology Course is an intensive laboratory course covering a diverse range of topics including molecular physiology, genetics, cell and molecular biology. This six week (14-16 hr/day) course is taken each summer by 36 graduate students, postdoctoral fellows, and physician-scientists beginning their basic research training. Each student participates in four of six ten-day research rotations that are taught by faculty teams consisting of at least two established investigators and one or more senior graduate students or postdoctoral fellows from the participating faculty's laboratories. This course offers extensive hands-on training in a wide range of experimental systems, rationales and methods. This training is facilitated by an array of state-of-the-art equipment loaned to the course (valued in excess of 2,250,000 dollars last year) by various manufacturers, which far exceeds the scope of the equipment available at the home institutions of most of our students. Emphasis is placed on experimental rationale, not methodologies, although expert training in state-of-the-art techniques is a clear byproduct of this emphasis. Laboratory training is augmented by daily lectures given by the faculty and other eminent scientists as well as through journal clubs, technical workshops and discussion groups where students can explore experimental rationales and the advantages and disadvantages of model systems. Research topics selected include those that highlight the unique aspects of the research/training environment of the MBL, which includes the areas of the cytoskeleton, signal transduction and imaging techniques. In 1996, students will chose to work in four of the following six laboratory sessions: (1) Analysis of membrane dynamics in vivo and training in advanced light microscopic imaging techniques with Jennifer Lippincott-Schwartz, Mark Terasaki and Edward Salmon, (2) Centrosomes, microtubule-based cytoskeleton dynamics and the utilization of marine organisms as model experimental systems with Roger Sloboda and Robert Palazzo, (3) Biochemical and structural analysis of molecular motors and the dynamics of the actin-based cytoskeleton with William Bement, Joseph Wolenski and Mark Mooseker, (4) Yeast genetics and molecular biology with Kerry Bloom, Daniel Lew and Elaine Yeh, (5) Cell-cycle regulation with Sally Kornbluth and Katherine Swenson, and (6) cell signaling mechanisms with Antony Galione and Ruth Empson. At the completion of the formal six-week course, students can apply for 2- 4 weeks of independent postcourse research, either with participating course faculty or with other investigators at the MBI.